For Loop exercises with solution

1. Displaying the first 10 natural numbers:

#include <stdio.h>

int main() {
    int i;
    printf("The first 10 natural numbers are:\n");
    for(i = 1; i <= 10; i++) {
        printf("%d ", i);
    }
    return 0;
}

2. Computing the sum of the first 10 natural numbers:

#include <stdio.h>

int main() {
    int i, sum = 0;
    printf("The first 10 natural numbers are:\n");
    for(i = 1; i <= 10; i++) {
        printf("%d ", i);
        sum += i;
    }
    printf("\nThe Sum is : %d", sum);
    return 0;
}

3. Displaying n terms of natural numbers and their sum:

#include <stdio.h>

int main() {
    int i, n, sum = 0;
    printf("Enter the number of terms: ");
    scanf("%d", &n);
    printf("The first %d natural numbers are:\n", n);
    for(i = 1; i <= n; i++) {
        printf("%d ", i);
        sum += i;
    }
    printf("\nThe Sum of Natural Number up to %d terms : %d", n, sum);
    return 0;
}

4. Reading 10 numbers from the keyboard and finding their sum and average:

#include <stdio.h>

int main() {
    int i, num;
    double sum = 0;
    printf("Input the 10 numbers:\n");
    for(i = 1; i <= 10; i++) {
        printf("Number-%d: ", i);
        scanf("%d", &num);
        sum += num;
    }
    printf("The sum of 10 numbers is: %.2lf\n", sum);
    printf("The Average is: %.6lf", sum / 10);
    return 0;
}

5. Displaying the cube of numbers up to an integer:

#include <stdio.h>

int main() {
    int i, n;
    printf("Input number of terms: ");
    scanf("%d", &n);
    printf("Expected Output:\n");
    for(i = 1; i <= n; i++) {
        printf("Number is: %d and cube of %d is: %d\n", i, i, i * i * i);
    }
    return 0;
}

6. Displaying the multiplication table for a given integer:

#include <stdio.h>

int main() {
    int i, num;
    printf("Input the number (Table to be calculated): ");
    scanf("%d", &num);
    printf("Expected Output:\n");
    for(i = 1; i <= 10; i++) {
        printf("%d X %d = %d\n", num, i, num * i);
    }
    return 0;
}

7. Displaying the multiplication table vertically from 1 to n:

#include <stdio.h>

int main() {
    int i, j, n;
    printf("Input upto the table number starting from 1: ");
    scanf("%d", &n);
    printf("Expected Output:\n");
    for(i = 1; i <= 10; i++) {
        for(j = 1; j <= n; j++) {
            printf("%dx%d = %d, ", j, i, j * i);
        }
        printf("\n");
    }
    return 0;
}

8. Displaying n terms of odd natural numbers and their sum:

#include <stdio.h>

int main() {
    int i, n, sum = 0;
    printf("Input number of terms: ");
    scanf("%d", &n);
    printf("Expected Output:\n");
    printf("The odd numbers are: ");
    for(i = 1; i <= n; i++) {
        printf("%d ", 2 * i - 1);
        sum += 2 * i - 1;
    }
    printf("\nThe Sum of odd Natural Number up to %d terms: %d", n, sum);
    return 0;
}

9. Displaying a right angle triangle pattern using asterisks:

#include <stdio.h>

int main() {
    int i, j, rows;
    printf("Enter the number of rows: ");
    scanf("%d", &rows);
    for(i = 1; i <= rows; i++) {
        for(j = 1; j <= i; j++) {
            printf("*");
        }
        printf("\n");
    }
    return 0;
}

10. Displaying a right angle triangle pattern with numbers:

#include <stdio.h>

int main() {
    int i, j, rows;
    printf("Enter the number of rows: ");
    scanf("%d", &rows);
    for(i = 1; i <= rows; i++) {
        for(j = 1; j <= i; j++) {
            printf("%d", j);
        }
        printf("\n");
    }
    return 0;
}

11. Pattern like a right-angle triangle with a number repeating in a row:

#include <stdio.h>

int main() {
    int n = 4; // Number of rows
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            printf("%d", i);
        }
        printf("\n");
    }
    return 0;
}

12. Pattern like a right-angle triangle with numbers increased by 1:

#include <stdio.h>

int main() {
    int n = 4; // Number of rows
    int num = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            printf("%d ", num);
            num++;
        }
        printf("\n");
    }
    return 0;
}

13. Pyramid pattern with numbers increased by 1:

#include <stdio.h>

int main() {
    int n = 4; // Number of rows
    int num = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = i; j < n; j++) {
            printf(" ");
        }
        for (int k = 1; k <= i; k++) {
            printf("%d ", num);
            num++;
        }
        printf("\n");
    }
    return 0;
}

14. Pyramid pattern with an asterisk:

#include <stdio.h>

int main() {
    int n = 4; // Number of rows
    for (int i = 1; i <= n; i++) {
        for (int j = i; j < n; j++) {
            printf(" ");
        }
        for (int k = 1; k <= i; k++) {
            printf("* ");
        }
        printf("\n");
    }
    return 0;
}

15. Calculate the factorial of a given number:

#include <stdio.h>

int main() {
    int num;
    unsigned long long factorial = 1;
    printf("Input the number: ");
    scanf("%d", &num);
    for (int i = 1; i <= num; i++) {
        factorial *= i;
    }
    printf("The Factorial of %d is: %llu\n", num, factorial);
    return 0;
}

16. Sum of n terms of even natural numbers:

#include <stdio.h>

int main() {
    int n, sum = 0;
    printf("Input number of terms: ");
    scanf("%d", &n);
    printf("The even numbers are: ");
    for (int i = 1; i <= n; i++) {
        printf("%d ", 2 * i);
        sum += 2 * i;
    }
    printf("\nThe Sum of even Natural Number up to %d terms: %d\n", n, sum);
    return 0;
}

17. Pyramid pattern with numbers repeating in the same row:

#include <stdio.h>

int main() {
    int n = 4; // Number of rows
    for (int i = 1; i <= n; i++) {
        for (int j = i; j < n; j++) {
            printf(" ");
        }
        for (int k = 1; k <= i; k++) {
            printf("%d ", i);
        }
        printf("\n");
    }
    return 0;
}

18. Sum of the series [1 - X^2/2! + X^4/4! - ...]:

#include <stdio.h>
#include <math.h>

int main() {
    int x, terms;
    double sum = 1.0; // First term is 1
    printf("Input the value of x: ");
    scanf("%d", &x);
    printf("Input the number of terms: ");
    scanf("%d", &terms);

    for (int i = 1; i < terms; i++) {
        int power = 2 * i;
        double term = pow(x, power) / tgamma(power + 1);
        if (i % 2 != 0) {
            term = -term;
        }
        sum += term;
    }

    printf("The sum = %lf\n", sum);
    printf("Number of terms = %d\n", terms);
    printf("Value of x = %d\n", x);
    return 0;
}

19. Display n terms of a harmonic series and their sum:

#include <stdio.h>

int main() {
    int n;
    double sum = 0.0;
    printf("Input the number of terms: ");
    scanf("%d", &n);
    printf("The harmonic series is: ");
    for (int i = 1; i <= n; i++) {
        printf("1/%d ", i);
        if (i < n) {
            printf("+ ");
        }
        sum += 1.0 / i;
    }
    printf("\nSum of Series up to %d terms: %lf\n", n, sum);
    return 0;
}

20. Pyramid pattern with asterisks with each row containing an odd number of asterisks:

#include <stdio.h>

int main() {
    int n = 3; // Number of rows
    int stars = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = i; j < n; j++) {
            printf(" ");
        }
        for (int k = 1; k <= stars; k++) {
            printf("*");
        }
        stars += 2;
        printf("\n");
    }
    return 0;
}